countassg.cc

// Access to C-Breeze functionality is in "c_breeze.h"
#include "c_breeze.h"

// This Walker counts assignments

class CountAssg: public Walker {
        int     _assgcount;     // keep count of the assignments

        public:
        CountAssg (void):       // constructor
                // we will walk the tree in preorder, visiting subtrees

                Walker (Preorder, Subtree),

                // initially the count is zero

                _assgcount(0) {}

        // override at_binary() of Walker
        // this function is called on every node representing a
        // binary operator.  'ord' tells us in what order the AST
        // is being visited, Preorder or Postorder; we don't need it yet.
        // binaryNode is a subclass of Node, a general AST node type.

        void at_binary (binaryNode *n, Order ord) {
                // if this binaryNode is an assignment, increment the count

                if (n->op()->is_assignment()) _assgcount++;
        }

        // return the number of assignments counted

        int assgcount(void) { return _assgcount; }
};

// This phase runs the CountAssg Walker on each translation unit.

class CountAssgPhase: public Phase {
        public:
        CountAssg               cw;     // an instance of the CountAssg Walker

        void run (void) {
                // an iterator through a list of translation units

                unit_list_p     u;

                // for each translation unit in the program...

                for (u=CBZ::Program.begin(); u!= CBZ::Program.end(); u++)

                        // ... walk the AST using the CountAssg walker

                        (*u)->walk (cw);

                // print the result to standard output

                cout << "number of assignments: " << cw.assgcount() << '\n';
        }
};

// This line causes C-Breeze to "see" the new Phase.  We name it "countassg"
// so that when we run C-Breeze from the command line, giving the option
// "-countassg" will invoke our phase.

Phases Phase ("countassg", new CountAssgPhase());

This code is pretty standard for a C-Breeze walker; you can customize it yourself to do many different things. If you're bothered by some of the conventions, don't worry. What's really important is the code in the CountId class; the rest is just stuff to make it go.